Replaceable bit rock drill



Aug.a 6, 1935.v

c. ER'lcKsoN REPLACEABLE BIT ROCK DRILL Filed Nov. 3, 1955 .a7 Il z QW,z5

2 Sheets-Sheet 2 Patented Aug. e, 193s UNITED STATES PATENT OFFICE iApplication November 3, 1933, Serial No. 696,509 6 Claims. (Cl. Z55-44)y tive shapes of stockv and bit whereby a loose iit is assured for thebit beyond the base and facilities for cooling provided within and aboutthe socket and bit as pointed out in the claims following adescription'in detail of the shape preferred in carrying out thisinvention.y

'I'he objects of the invention are to eliminate the breakages of the'jaws of the stock .-lof the drill following the sharp blows incident-to the operations of drilling holes .and the consequent impacts of thebits with the rock, thereby avoiding troubleand delay in the replacementof the drills and materially increasing the speed and eiiiciency incarrying on the work in mining and contracting and at the same timeeconomizing in so far as the consumption of steel is concerned throughthe expenditures of money in labor and power in transporting quantities`oi' ymetal sometimes to almost inaccessible places; to construct astock and bit which will contain provisions for a constant ow of waterand consequently keep the bit cool throughout the drilling operation;

and generally to overcome the difliculties incident to the use of adrill of this classication and hitherto found to be troublesome in thematter of fractured jaws.

In the drawings, Figure 1 is an end elevation view of the bit and drillassembled showing the stock broken away. Y

Figure 2 is a side elevational view of the assembled bit and drillshowing the stock broken away.

Figure 3 is a longitudinal sectional view of the stock broken away andof the bit within the socket and taken on the lines 2-3 in Figure 2.

Figure 4 is a longitudinal sectional view of the stock taken on thelines 5 4 in Figure 1 with the bit removed.

Figure 5 is a cross sectional view through the complete drill taken onthe lines 5 5 in Figure l.

Figure 6 is a cross sectional view through the complete drill taken onthe lines 6--0 in Figure 1.

Figure 'Z is a cross sectional view through the complete drill taken onthe lines 1-1 in Fig7 ure 1.

Figure 8 is a cross sectional view of the b inserted in the socket ofthe stock and taken on the lines l in Figure 1.

t Figure 9 is a plan view` of the upset head of the s oc Figure 10 is aplan view of the underside of the bit.

Like numerals of reference indicate corre- 5 sponding parts in thevarious ilgures.

Referring to the drawings, the bit is indicated by the numeral I5 andthe shape of this bit is all important in relation to its holder for inits impacts with the rock following the blows on l0 the holder, theresults from these impacts must `not aiect the holder in s uch a way asto cause a fracture, therefore the base I6 on the bit should be flat andits head I1, a form of spear-shape in cross section omitting any barbs,while the thick- 15 ness through the bit at the extremities of the head,much the same as through the extremities of the bit at the base. V

The bevels IIA form the sides of the head I1 and terminate in thecutting edge I 8 of the head. 'I'he 20 neck I9 is formed by the inwardlycurving surfaces 20 on either side, extended into the surfaces on eitherside of the shank portion 2|, so that the bit in cross section isobtapering shape from the base to the neck, or in other words, the bithas 25 a `tapered shank Yfor the side walls and extends outwardly on theconvergentlines as far as the neck.

Along the base of the bit, the water groove 22 extends from end to end,while the corners be- 30 tween the fiatr base and theshank surfaces are'bevelled at both sides and ends as shown at 23.

The stock indicated by the numeral 24 is preferably a bar of steel upsetat one end and slotted at the upset end to form the jaws 26 and 2i, 35comprising a socket 21 for the bit and the inner wall surfaces of thesejaws extend outwardly in convergentV lines of direction from the flatbase 28 which is between the illlets 22 and 3l roughly corresponding tothe bevels 22 of the bit.

The convergent lines of the inner wall surfaces of the socket 21 form alonger taper from substantially the same base as the bit or nearly so,consequently, there are formed on either side of the bit, the spaces IIand I2 widening out from the bases of bit and stock in the direction ofthe outer endof the stock. naturally the result is that room ispermitted in the socket for the slight upsetting of the bit due to itsimpacts on the rock.

The jaws 25 and 2l are chamfered at the outer ends 3l and 24 tofacilitate a passage of chips on either side of the bit from the endsurfaces 2l and 26 and on either side of these chamfered surfaces thecorners are bevelled in each instance. as shown at 31 and 33.

The central water channel 39 within the stock empties into the socket 21centrally and the central cross grooves 40 and 4I in the fiat base 28 ofthe socket 21 register with the feed water channel 39. The slots 42 and43 are respectively cut into the jaws 25 and 26 midway of the length ofthese jaws and the 4inner corners of the walls forming the said jaws atthe ends thereof are chamfered oi at 44 and 45 to reduce the contactingsurface with the bit. v

The slots 42 and 43 register with cross slots 46 and 41 communicatingwith the main water channel 39, therefor, there is an assurance of acontinuous supply of water around the bit an in the hole drilled.

The shank of the bit I5 may be formed of softer texture than the head orblade portion which is rather an important feature for the very goodreason that the metal of the shank necessarily becomes upset in itssocket to a very slight extent but sufliciently to take the earliereifects of the impact or in other words to sustain the ilrst shock,which is all important in any holding device.

In the use of this tool, the bit is inserted from one side and settlesitself in the socket through the impact. 'I'he natural result of theoriginal blows is to upset the shank of the bit a trifle so that itbecomes thicker from the lower part of the neck inwardly and the resultof this is that the spaces 3| and 32 are filled up, but not before thebit has settled in its own place and it will be noticed that the fullforce of the blow is taken on the at base, and as each shock occurs, thebit broadens out in so far as thickness is concerned upwardly from thebase until it is well established in the socket, that is to say, untilthe spaces are completely filled up and any further upsetting may occuron the turned corners, consequently there is really no jar of any momenton the jaws at all, and by the .time the spaces 3l and 32 are wellillled up, the metal of the bit is like a lling of a hole between hardersurfaces, and any impact on that filling causes little or no eifect onthe harder surfaces which are here represented by the jaws.

What I claim is:

1. In a replaceable rock drill stock and bit, a bit formed with a. headand base and an intervening shank and a longitudinal water groove acrossthe base and a stock suitably formed to receive the bit.

2. In a replaceable rock drill stock and bit, a stock having alongitudinal Ywater channel therewithin and a socket at one end toreceive a bit, said socket having a flat base and water groovesthereacross registering with said feed water channel, and a bitcorrespondingly formed to instantly iit in said. socket.

3. In a replaceable rock 'drill stock and bit, a stock having alongitudinal water channel therewithin and a socket formed of jawsslotted centrally forming Water outlets registering with cross slots inturn registering with the central water feed channel.

4. In a replaceable rock drill stock and bit, a stock having alongitudinal water channel therewithin, and a socket at one end toreceive a bit, said socket having a flat base and a Water groove thereacross registering with the longitudinal water channel, and jawsprojecting upwardly and forming a part of said socket slotted centrallyand extending below the level of the socket base, and forming groovestherein at right angles to the water grooves and leading into the waterchannel, and a bit correspondingly formed to instantly ilt in saidsocket.

5. In a replaceable rock drill stock and bit, a stock having alongitudinal-water channel therewithin and forming a bit socket havingupwardly tapering walls slotted centrally forming water outletsregistering with the cross slots in turn registering with the centralwater feed channel, and a bit in cross sectional shape tapering insharper converging lines than the socket walls and becominga looser iltoutwardlyv from the socket and terminating in a blade portion.

6. In a replaceable rock drill stock and bit, a slotted cylindricalstock forming a bit socket and having a longitudinal water channeltherewithin, side walls converging upwardly and inwardly from the baseof said socket to form jaws and slotted centrally and having shouldersat the top bevelled olf on the sides to form naps, the base of saidsocket having water grooves thereacross registering with the waterchannel, a bit having a fiat base and correspondingly formed toinstantly i'lt in said socket and a 'longitudinal water groove acrossthe base of the bit and corresponding with the water groove across thebase of said socket.

CHARLES ERICKSON.

